Double-acting two-stroke-cycle internal-combustion engine



Nov. 27, 1928.

- G. DRUMMOMD nousm: AcmNe TWO-STROKE cYcLE INTERNAL COMBUSTION ENGINE Filed June 2, 1923 llfl'i ililllllflli Patented Nov. 27, 1928.

UNITED STATES,

PATENT OFFICE.

GERALDDRUMMOND, OF WORCESTER, ENGLAND.

DOUBLE-ACTING TWO-STROKE-CYCLE INTERNAL-CQMBUSTION ENGINE.

Application filed June2, 1923,.Serial No 643,048, and in Great Britain August 14, 1922.

This invention relates to'an internal combustion engine operating on theDieselprim ciple, that is, wherein the heat'ofcompression of air causesignition ofv injected fuel. Ac-

cording to this invention, a power stroke is effected everyv halferevolution of the'drivenengine shaft Further, the inventionlends itself to theproduction-of a compact power unit of clean external appearance and there are no reactionary thrusts on, cylinder supporting members etc., such as are met with in many ordinary engines. The improved engine is easily balanced, and possesses the. further ad vantage of controlled reversibility.

According to this invention,two pistons are mounted in a cylinder, slidable but unrotatable therein, and they are arranged co-operatively to drive ashaft parallel tofthe axis of the cylinder, through members engaging inclinedsurfaces formed on or rigidly with the shaft. The inclined surfaces are so arranged that the pistons reciprocate symmetrically,

that is, they approach together, stop, move 'apart, stop,and repeat this cycle. Thespace between them forms one combustion chamber, andthe spaces betweenthe cylinder ends and pistons form two other. chambers which are in effect one, andmay ifdesired be connected by suitableducts. Further, according to the invention, the shaft may be coaxial with the cylinder and pass through the. pistons and cylinder end plates. In this case,'the pistons are connected to sleeves which may slide but not rotate in glands in the end plates, and which carry at their outer ends anti-friction devices engaginginclined surfaces preferably in the form of grooves cut in the shaft, which rotates within the sleevesand preferably also within an insulating sleeve which protects it from the high temperature of the combustion chambers. The. combustion chambers have valves forthe emission and admisison of gases andalso fuel injection valves. The engine is provided with a fuel distributor which allows of timing the injection of fuel, as will be seen, and thus allows of reversal of the engine by timing. This device will be better understood from the following description ofa preferred formof the engine, wherein reference is made to the'drawing, of which Fig. 1 is a part sectional elevation of the en a,

Fig. 2 is a sectional View of the distributor.

Fig. 3 is a sectional plan view of the same.

The engine shown is of horizontal type with one cylinder. It will be understood of course, that a plurality of cylinders may be used, coupled up or on one shaft, if desired.

The cylinder barrel 1 has pistons 2 mounted at the inner endsv ofQsleevcs 3 which pass through the end plates 4 through suitable packing glands 5. The sleeves 3 are splined or otherwiseprevented from rotating as will be described. The outer ends of the sleeves carry housings in each of which is a free ball 6 preferably held in place by a threaded plug The balls 6 run in grooves 8 formed in the thickened portions 9 of the engine shaft 10 which is co-axial with the cylinder 1.

The grooves are in the form of interrupted helices each passing nearly half way around the shaft, and returning, so that a continuous track ,is formed in'wliich a ball 6 runs. Re ciprocation of the pistons causes rotation of the shaft and a flywheel 11 is fitted in the described form to carry the shaft. over the deadeentres formed by the apices of the grooves. The grooves are so disposed that their apices correspond andare symmetrical at each end of the shaft,'thus the'pistons move symmetrically as stated.

Betweenthe sleeves 3 and shaft 10 there is a sufiicient space left for the insulating sleeve 12 which surrounds the shaft 10, and on which the pistons 2 slide. A sutable bearing 13 enables the shaft 10 to rotate easily within the ions 16 serves to drive camshafts 17 18 on each side of the engine, the camshafts bearmg cams 19 co-operating with rockers 20 which for Diesel engine service, injects air under compression into whichever chamber has an open inlet valve, and the ingomg a1r scavenges Or h lps to scavenge the products of the last explosion in that chamber. through the exhaust valve which simultaneously opened or timed withoverlap. From the camshaft 18 is drivena sh aft 22 which drives the fuel distributor which a feature of the invention. The distributor comprises a casing or chamber 23, with a coverplate 24L incorporatin a pipe union 25 connected to the pressure-fed liquid fuel source. has three leac s 26 from it, disposed as shown, 90 apart and contains an annular block 27 which is partiallyrotatable say, through the medium of a boss 28 projecting through an arcuate slot in the casing 23. The interior of this block is cored out into a conical bore. and conical valve member 29 rotated by the shaft 22, is shaped to conform with the interior of the block and to be a liquid-tight t therein. The valve member29-has two orts 30 disposed shown at 180 and in the otation of the member 29 the portsSO register alternately with two opposite channels in the block 27 or with one channel between the opposed pair. The channels in the members 27 are made tapered or bell-mouthed with a narrower opening towards the valvemember 29 than to the leads 26. Thus the block 27 maybe rotatedthrough a considerable angle, retardingor advancing the moment when a clear passage is opened between the interior of valve 29 and the leads 26. The pressure fed fuclflis, of course, fed into the inside of the valve for distribution, whence it is allowed in the course of rotation of the valve member to flow either to the chamber between the pistons 2 or to the chambers at the ends of the cylinder. ihe fuel is actually admitted from'the leads 26 tothe cylinder through needle valves of the type shown orany other suitable type. As shown, a needle-valve stem 31 is provided in a pressure resisting housing 32, with its spring all enclosed. The valve unit is screwed into the cylinder at Bl and so is easily removable as whole. A spraying or other suitable jet may be provided if dc- L ated, as will be obvious.

In the engine illustrated, the pistons are prevented from rotation by the provision on the sleeves 3 of a sliding block 35 running in a track 36 formed in the framework 37 of the )"ojection on to a hot spot, may be incorpor- The chamber 23.

sired, and any lmown practice such as fuel movement of thepistons into rotary move-;

ment of the shaft, means whereby the pistons are adapted to be reciprocated in the cyllnder simultaneously towards and from each other,

the portions of the cylinder on both sides of the pistons constituting combustion chambers, and a sleeve in the cylinder 'surrounding the shaft to constitute a heat insulator for the shaft. V j 1 2. An engine having, in combination, a cylinder, a frame having a fixed track, two

members, one a shaft and the other asleeve surrounding the'shaft, the sleeve having a slide engaging the trackto permit reciprocating movement of the sleeve and to prevent rotary movement of the sleeve, a piston fixed to the sleeve within the cylinder, one of the members having a continuous spiral groove and the other member having an element projecting into the groove, and means for reciprocating the sleeve longitudinally of the shaft to effect the rotation of the shaft through the groove-and-element connection.

3. An internal-combustionv engine having, in combination, a closed cylinder, two pistons reciprocally mounted in the cylinder, the portions of the cylinder on both sides ofthe pistons constituting combustion chambers,

each combustion chamber "being" provided Witha valve, means for injecting fuel into the cylinder through the valves at predetermined times to efiect simultaneous reciproeating movement of the pistons symmetrically towards and from each other in the cylinder at predetermined times, a fuel-distributmgvalve connected with the valves for advancing and retarding the injection of the fuel, and meanscontrolled by the operation of the pistons for controlling the operation of the fuel distributor. i j

4;. An internal-combustion enginehaving, in combination, a closed cylinder, a shaft disposed in the cylinder and projecting therefrom at each end thereof, a sleeve surrounding each outer end of the shaft,: the sleeves being non-rotatably mounted'w'ith respect to thecylinder but being adapted to reciprocate longitudinally of the shaft, the outer end of each sleeve projecting through the corresponding end of the cylinder, a piston fixed to the inner end of each sleeve within the cylinder, the portions of the cylinder on both sides of the pistons constituting combustion chambers, the shaft being provided with two continuous spiral grooves, the sleeves each having an element engaging in one of the grooves, whereby the sleeves are connected with the shaft to always convert reciprocating movement of the pistons and consequent longitudinal movement of the sleeves upon the shaft into rotary movement of the shaft, and means for injecting fuel in the intermediately disposed chamber and in the other two chambers alternately to efiect simultaneous reciprocating movement of the pistons symmetrically towards and from each other in the cylinder longitudinally of the shaft to effect the rotation of the shaft through the groove-and-element connections.

In Witness whereof I have signed this specifioation.

GERALD DRUMMOND. 

